/*
 * WorldEdit, a Minecraft world manipulation toolkit
 * Copyright (C) sk89q <http://www.sk89q.com>
 * Copyright (C) WorldEdit team and contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package com.sk89q.worldedit.extension.factory.parser.pattern;

import com.sk89q.util.StringUtil;
import com.sk89q.worldedit.WorldEdit;
import com.sk89q.worldedit.extension.input.InputParseException;
import com.sk89q.worldedit.extension.input.ParserContext;
import com.sk89q.worldedit.function.pattern.Pattern;
import com.sk89q.worldedit.function.pattern.RandomPattern;
import com.sk89q.worldedit.internal.registry.InputParser;
import com.sk89q.worldedit.util.formatting.text.TextComponent;
import com.sk89q.worldedit.util.formatting.text.TranslatableComponent;

import java.util.List;
import java.util.stream.Stream;

public class RandomPatternParser extends InputParser<Pattern> {

    private final java.util.regex.Pattern regex = java.util.regex.Pattern.compile("[0-9]+(\\.[0-9]*)?%.*");

    public RandomPatternParser(WorldEdit worldEdit) {
        super(worldEdit);
    }

    @Override
    public Stream<String> getSuggestions(String input, ParserContext context) {
        String[] splits = input.split(",", -1);
        List<String> patterns = StringUtil.parseListInQuotes(splits, ',', new char[] {'[', '{' }, new char[] {']', '}'}, true);
        // get suggestions for the last token only
        String percent = null;
        String token = patterns.get(patterns.size() - 1);
        if (regex.matcher(token).matches()) {
            String[] p = token.split("%", 2);
            percent = p[0];
            token = p[1];
        } else if (patterns.size() == 1) {
            return Stream.empty(); // handled by DefaultBlockParser
        }
        String previous = patterns.size() == 1 ? "" : String.join(",", patterns.subList(0, patterns.size() - 1)) + ",";
        String prefix = previous + (percent == null ? "" : percent + "%");
        final List<String> innerSuggestions = worldEdit.getPatternFactory().getSuggestions(token, context);
        return innerSuggestions.stream().map(s -> prefix + s);
    }

    @Override
    public Pattern parseFromInput(String input, ParserContext context) throws InputParseException {
        RandomPattern randomPattern = new RandomPattern();

        String[] splits = input.split(",", -1);
        List<String> patterns = StringUtil.parseListInQuotes(splits, ',', new char[] {'[', '{' }, new char[] {']', '}'}, true);
        if (patterns.size() == 1) {
            return null; // let a 'single'-pattern parser handle it
        }
        for (String token : patterns) {
            double chance;
            Pattern innerPattern;

            // Parse special percentage syntax
            if (token.matches("[0-9]+(\\.[0-9]*)?%.*")) {
                String[] p = token.split("%");

                if (p.length < 2) {
                    throw new InputParseException(TranslatableComponent.of("worldedit.error.parser.missing-random-type", TextComponent.of(input)));
                } else {
                    chance = Double.parseDouble(p[0]);
                    innerPattern = worldEdit.getPatternFactory().parseFromInput(p[1], context);
                }
            } else {
                chance = 1;
                innerPattern = worldEdit.getPatternFactory().parseFromInput(token, context);
            }

            randomPattern.add(innerPattern, chance);
        }

        return randomPattern;
    }
}
